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chapterWorking at height

3OVERVIEW Most construction trades require frequent use of some type of working platform or access equipment. Working off the ground can be dangerous and the greater the height the more serious the risk of injury. This chapter will give you a summary of some of the most common types of access equipment and provide information on how they should be used, maintained and checked to ensure that the risks to you and others are minimal.

This chapter will cover the following topics:

• Generalsafetyconsiderations

• Stepladdersandladders

• Roofwork

• Trestleplatforms

• Hop-ups

• Scaffolding

• Fallprotection.

These topics can be found in the following modules:

CC1001K CC1001S

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Brickwork NVQ and Technical Certificate Level 2, 2nd Edition

General safety considerationsYou will need to be able to identify potential hazards associated with working at height, as well as hazards associated with equipment. It is essential that access equipment is well maintained and checked regularly for any deterioration or faults, which could compromise the safety of someone using the equipment and anyone else in the work area. Although obviously not as important as people, equipment can also be damaged by the use of faulty access equipment. When maintenance checks are carried out they should be properly recorded. This provides very important information that helps to prevent accidents.

Risk assessmentBefore any work is carried out at height, a thorough risk assessment needs to be completed. Your supervisor or someone else more experienced will do this while you are still training, but it is important that you understand what is involved so that you are able to carry out an assessment in the future.

Foraworkingatheightriskassessmenttobevalidandeffectiveanumberofquestions must be answered:

1.Howisaccessandegresstotheworkareatobeachieved?

2.Whattypeofworkistobecarriedout?

3.Howlongistheworklikelytolast?

4.Howmanypeoplewillbecarryingoutthetask?

5.Howoftenwillthisworkbecarriedout?

6.Whatistheconditionoftheexistingstructure(ifany)andthesurroundings?

7.Isadverseweatherlikelytoaffecttheworkandworkers?

8.Howcompetentaretheworkforceandtheirsupervisors?

9.Istherearisktothepublicandworkcolleagues?

DutiesYour employer has a duty to provide and maintain safe plant and equipment, which includes scaffold access equipment and systems of work.

You have a duty:

• to comply with safety rules and procedures relating to access equipment

• to take positive steps to understand the hazards in the workplace and report things you consider likely to lead to danger, for example a missing handrail on a working platform

• not to tamper with or modify equipment.

Did you know?

Only a fully trained and competent person is allowed to erect any kind of working platform or access equipment. You should therefore not attempt to erect this type of equipment unless this describes you!

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Chapter 3 Working at height

Stepladders and laddersStepladdersA stepladder has a prop, which when folded out allows the ladder to be used withouthavingtoleanitagainstsomething.Stepladdersareoneofthemostfrequently used pieces of access equipment in the construction industry and are often used every day. This means that they are not always treated with the respecttheydemand.Stepladdersareoftenmisused–theyshouldonlybeusedfor work that will take a few minutes to complete. When work is likely to take longer than this, a sturdier alternative should be found.

When stepladders are used, the following safety points should be observed:

• Ensurethegroundonwhichthestepladderistobeplacedisfirmandlevel.Ifthe ladder rocks or sinks into the ground it should not be used for the work.

• Always open the steps fully.

• Never work off the top tread of the stepladder.

• Always keep your knees below the top tread.

• Never use stepladders to gain additional height on another working platform.

• Always look for the kitemark, which shows that the ladder has been made to BritishStandards.

A number of other safety points need to be observed depending on the type of stepladder being used.

Wooden stepladderBefore using a wooden stepladder:

• Check for loose screws, nuts, bolts and hinges.

• Check that the tie ropes between the two sets of stiles are in good condition and not frayed.

• Check for splits or cracks in the stiles.

• Check that the treads are not loose or split.

Never paint any part of a wooden stepladder as this can hide defects, which may cause the ladder to fail during use, causing injury.

HeinemannNVQ2 Carpentry9pt Zurich BTfig0175

Figure 3.1 British Standards Institution kitemark

Wooden stepladder

Definition

Stiles – the side pieces of a stepladder into which the steps are set

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Aluminium stepladderBefore using an aluminium stepladder:

• check for damage to stiles and treads to see whether they are twisted, badly dented or loose

• avoid working close to live electricity supplies as aluminium will conduct electricity.

Fibreglass stepladderBeforeusingafibreglassstepladder,checkfordamage to stiles and treads. Once damaged, fibreglassstepladderscannotberepairedandmust be disposed of.

LaddersA ladder, unlike a stepladder, does not have a prop and so has to be leant against something in order for it to be used. Together with stepladders, ladders are one of the most common pieces of equipment used to carry out work at heights and gain access to the work area.

Aswithstepladders,laddersarealsoavailableintimber,aluminiumandfibreglassand require similar checks before use.

Ladder typesPole ladder

These are single ladders and are available in a range of lengths. They are most commonly used for access to scaffolding platforms. Pole ladders are made from timberandmustbestoredundercoverandflat,supported evenly along their length to prevent them sagging and twisting. They should be checked for damage or defects every time before being used.

Extension ladder

Extension ladders have two or more interlocking lengths, which can be slid together for convenient storage or slid apart to the desired length when in use.

Aluminium stepladder

Safety tip

If any faults are revealed when checking a stepladder, it should be taken out of use, reported to the person in charge and a warning notice attached to it to stop anyone using it

Find out

What are the advantages and disadvantages of each type of stepladder?

Did you know?

Stepladders should be stored under cover to protect from damage such as rust or rotting

Pole ladder

Safety tip

Ladders must NEVER be repaired once damaged and must be disposed of

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Extensionladdersareavailableintimber,aluminiumandfibreglass.Aluminiumtypes are the most favoured as they are lightweight yet strong and available in doubleandtripleextensiontypes.Althoughalsoverystrong,fibreglassversionsareheavy,makingthemdifficulttomanoeuvre.

Erecting and using a ladderThe following points should be noted when considering the use of a ladder:

• As with stepladders, ladders are not designed for work of long duration. Alternative working platforms should be considered if the work will take longer than a few minutes.

• The work should not require the use of both hands. One hand should be free to hold the ladder.

• You should be able to do the work without stretching.

• You should make sure that the ladder can be adequately secured to prevent it slipping on the surface it is leaning against.

Pre-use checks

Before using a ladder check its general condition. Make sure that:

• no rungs are damaged or missing

• the stiles are not damaged

• no tie-rods are missing

• no repairs have been made to the ladder.

In addition, for wooden ladders ensure that:

• they have not been painted, which may hide defects or damage

• there is no decay or rot

• the ladder is not twisted or warped.

Erecting a ladder

Observe the following guidelines when erecting a ladder:

• Ensure you have a solid, level base.

• Do not pack anything under either (or both) of the stiles to level it.

• If the ladder is too heavy to put it in position on your own, get someone to help.

• Ensurethatthereisatleastafour-rungoverlaponeachextensionsection.

Aluminium extension ladder

Did you know?

On average in the UK, 14 people a year die at work falling from ladders; nearly 1,200 suffer major injuries (source: Health and Safety Executive)

Definition

Tie-rods – metal rods underneath the rungs of a ladder that give extra support to the rungs

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• Never rest the ladder on plastic guttering as it may break, causing the ladder to slip and the user to fall.

• Where the base of the ladder is in an exposed position, ensure it is adequately guarded so that no one knocks it or walks into it.

• The ladder should be secured at both the top and bottom. The bottom of the ladder can be secured by a second person, however this person must not leave the base of the ladder whilst it is in use.

• The angle of the ladder should be a ratio of 1:4 (or 75°). This means that the bottom of the ladder is 1 m away from the wall for every 4 m in height (seeFigure3.2).

• The top of the ladder must extend at least 1 m, or 5 rungs, above its landing point.

Roof workWhen carrying out any work on a roof, a roof ladder or crawling board must beused.Roofworkalsorequirestheuseofedgeprotectionor,wherethisisnotpossible, a safety harness.

The roof ladder is rolled up the surface of the roof and over the ridge tiles, just enough to allow the ladder to be turned over and the ladder hook allowed to bear on the tiles on the other side of the roof. This hook prevents the roof ladder sliding down the roof once it is accessed.


1 m

4 m

Figure 3.2 Correct angle for a ladder

Remember

You must carry out a thorough risk assessment before working from a ladder. Ask yourself, ‘Would I be safer using an alternative method?’

Definition

Crawling board – a board or platform placed on roof joists which spread the weight of the worker allowing the work to be carried out safely

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Trestle platformsA trestle is a frame upon which a platform or other type of surface (e.g. a table top) can be placed. A trestle should be used rather than a ladder for work that will take longer than a few minutes to complete. Trestle platforms are composed of the frame and the platform (sometimes called a stage).

FramesA-framesThese are most commonly used by carpenters and painters. As the name suggests, the frame is in the shape of a capital A and can be made from timber, aluminiumorfibreglass.Twoareusedtogether to support a platform (a scaffold or stagingboard).SeeFigure3.4.


Make sure that theladder extends atleast three rungsabove the base ofthe roof ladder

Use a ladder standoff to prevent theaccess ladderbearing onto theplastic gutter

Roofladder

Wheel

Figure 3.3 Roof work equipment


Figure 3.4 A-frame trestles with scaffold board

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WhenusingA-frames:

• they should always be opened fully and, in the same way as stepladders, must beplacedonfirm,levelground

• the platform width should be no less than 450 mm

• the overhang of the board at each end of the platform should be not more than four times its thickness.

Steel trestlesThesearesturdierthanA-frametrestlesandareadjustableinheight.Theyarealsocapableofprovidingawiderplatformthantimbertrestles–seeFigure3.5.AswiththeA-frametype,theymustbeusedonlyonfirmandlevelgroundbutthetrestleitselfshouldbeplacedonaflatscaffoldboardontopoftheground. Trestlesshouldnotbeplacedmorethan1.2mapart.

Safety tip

A-frame trestles should never be used as a stepladder as they are not designed for this purpose

Figure 3.5 Steel trestle with staging board HeinemannNVQ2 Carpentry9pt Zurich BTfig0179

PlatformsScaffold boardsTo ensure that scaffold boards provide a safe working platform, before using them check that they:

• are not split

• are not twisted or warped

• have no large knots, which cause weakness.

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Staging boardsThese are designed to span a greater distance than scaffold boards and can offer a 600 mm wide working platform. They are ideal for use with trestles.

Hop-upsAlsoknownasstep-ups,theseareidealforreachinglow-levelworkthatcanbecarriedoutinarelativelyshortperiodoftime.Ahop-upneedstobeofsturdyconstructionandhaveabaseofnotlessthan600mmby500mm.Hop-upshavethe disadvantage that they are heavy and awkward to move around.

ScaffoldingTubular scaffold is the most commonly used type of scaffolding within the construction industry. There are two types of tubular scaffold:

1.Independentscaffold–free-standingscaffoldthatdoesnotrelyonanypartofthe building to support it (although it must be tied to the building to provide additional stability).

2.Putlogscaffold–scaffoldingthatisattachedtothebuildingviatheentryofsome of the poles into holes left in the brickwork by the bricklayer. The poles stay in position until the construction is complete and give the scaffold extra support.

Nooneotherthanaqualifiedcarded scaffolder is allowed to erect or alter scaffolding. Although you are not allowed to erect or alter this type of scaffold, you must be sure it is safe before you work on it. You should ask yourself a number of questions to assess the condition and suitability of the scaffold before you use it:

• Are there any signs attached to the scaffold which state that it is incomplete or unsafe?

• Isthescaffoldoverloadedwithmaterialssuchasbricks?• Aretheplatformsclutteredwithwastematerials?• Arethereadequateguardrailsandscaffoldboardsinplace?• Does the scaffold actually looksafe?

• Istherethecorrectaccesstoandfromthescaffold?• Arethevariousscaffoldcomponentsinthecorrectplace(seeFigure3.6)?• Havethecorrecttypesoffittingsbeenused(seeFigure3.7)?

Safety tip

Do not use items as hop-ups that are not designed for the purpose (e.g. milk crates, stools or chairs). They are usually not very sturdy and can’t take the weight of someone standing on them, which may result in falls and injury

Definition

Carded scaffolder – someone who holds a recognised certificate showing competence in scaffold erection

Did you know?

It took 14 years of experimentation to finally settle on 48 mm as the diameter of most tubular scaffolding poles

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Remember

If you have any doubts about the safety of scaffolding, report them. You could very well prevent serious injury or even someone’s death

Figure 3.6 Components of a tubular scaffolding structure


Toe board Toe board andguard rails fixedto standards

Close boardedplatform (workingplatform)

Ledgers(horizontaltubes fittedto standardsto keep themapart)

Through tie(ties scaffoldto mainstructure)

Base plates

Sole plates (for evenweight distribution)

Ledger bracingLongitudinal bracingFacade bracing(firms up the structure, bracingis provided diagonally)

Transoms (supportfor boards and helpkeep standards anequal distance apart)

Standards(upright tubes)


Right angle coupler – loadbearing; used to jointubes at right angles

Universal coupler – loadbearing; also used tojoin tubes at right angles

Swivel coupler – load bearing;used to join tubes at variousangles, e.g. diagonal braces

Adjustable base plate orbase plate used at the baseof standards to allow evenweight distribution

Figure 3.7 Types of scaffold fittings

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Mobile tower scaffoldsMobile tower scaffolds are so called because they can be moved around without being dismantled. Lockable wheels make this possible and they are used extensively throughout the construction industry by many different trades. A tower can be made from eithertraditionalsteeltubesandfittingsoraluminium,whichislightweight and easy to move. The aluminium type of tower is normally specially designed and is referred to as a ‘proprietary tower’.

Low towersThese are a smaller version of the standard mobile tower scaffold andaredesignedspecificallyforusebyoneperson.Theyhavearecommendedworkingheightofnomorethan2.5mandasafeworking load of 150 kg. They are lightweight and easily transported and stored.

These towers require no assembly other than the locking into place oftheplatformandhandrails.However,youstillrequiretrainingbefore you use one and you must ensure that the manufacturer’s instructions are followed when setting up and working from this type of platform.


Figure 3.8 Mobile tower scaffold


Figure 3.9 Low tower scaffold

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Erecting a tower scaffoldItisessentialthattowerscaffoldsaresituatedonafirmandlevelbase.Thestability of any tower depends on the height in relation the size of the base:

• Foruseinsideabuilding,theheightshouldbenomorethanthree-and-a-halftimes the smallest base length.

• Foroutsideuse,theheightshouldbenomorethanthreetimesthesmallestbase length.

The height of a tower can be increased provided the area of the base is increased proportionately.Thebaseareacanbeincreasedbyfittingoutriggerstoeachcorner of the tower.

Formobiletowers,thewheelsmustbeinthelockedpositionwhilsttheyareinuseand unlocked only when they are being repositioned.

There are several important points you should observe when working from a scaffold tower:

• Anyworkingplatformabove2mhighmustbefittedwithguardrailsandtoeboards.Guardrailsmayalsoberequiredatheightsoflessthan2mifthereis a risk of falling onto potential hazards below, for example reinforcing rods. Guardrailsmustbefittedataminimumheightof950mm.

• If guardrails and toe boards are needed, they must be positioned on all four sides of the platform.

• Anytowerhigherthan9mmustbesecuredtothestructure.• Towersmustnotexceed12minheightunlesstheyhavebeenspecifically

designed for that purpose.

• The working platform of any tower must be fully boarded and be at least 600 mm wide.

• If the working platform is to be used for materials then the minimum width must be 800 mm.

• All towers must have their own access and this should be by an internal ladder.

Fall protectionWith any task that involves working at height, the main danger to workers is falling. Although scaffolding, etc. should have edge protection to prevent falls, there are certain tasks where edge protection or scaffolding simply cannot be used.

Definition

Proportionately – in relation to the size of something else

Safety tip

Mobile towers must only be moved when they are free of people, tools and materials

Safety tip

Never climb a scaffold tower on the outside as this can cause it to tip over

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In these instances some form of fall protection must be in place to prevent the worker falling, keep the fall distance to a minimum or ensure the landing point is cushioned.

There are various different types of fall protection available but the most common used are:

• harness and lanyards

• safety netting

• air bags.

Harness and lanyardsHarnessandlanyardsareatypeoffall-arrestsystem,whichmeansthat,intheevent of a slip or fall, the worker will only fall a few feet at most.

The system works with a harness that is attached to the worker and a lanyard attached to a secure beam/eyebolt. If the worker slips, then they will only fall as far as the length of cord/lanyard and will be left hanging, rather than falling to the ground.

Safety netting Safetynettingisalsoatypeoffall-arrestsystembutisusedmainlyonthetopfloorwherethereisnohigherpointtoattacha lanyard.

Primarilyusedwhendeckingroofing,thenetsareattachedtothe joists/beams and are used to catch any worker who may sliporfall.Safetynettingisalsousedoncompletedbuildingswhere there is a fragile roof.

A harness and lanyard can prevent a worker from falling to the ground

Safety netting is used when working at the highest point

Safety netting can be used under fragile roofs

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Air bagsAnairbagsafetysystemisaformofsoftfall-arrestandiscomprisedofinterlinkedmodular air mattresses. The modules are connected by push connectors and/or flexiblecouplingsandareinflatedbyapump-drivenfan,whichcanbeelectric,petrol,orbutanegaspowered.Astheindividualairbagsfillwithlow-pressureair, they expand together to form a continuous protective safety surface, giving a cushioned soft fall and preventing serious injury.

Thesystemmustbekeptinflatedand,ifitisrunonpetrolorgas,shouldbechecked regularly to ensure that it is still functioning. This system is ideal for short fall jobs, but should not be used where a large fall could occur.

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Am I protected from electrocution if I am working on a wooden stepladder?No. If you are working near a live current on a wooden stepladder, if any metal parts of the ladder, such as the tie rods, come into contact with the current,theywillconducttheflowofelectricityandyoumaybeelectrocuted.Takeeveryprecautionpossibleinordertoavoidtheriskofelectrocution–thesimplest precaution is turning off the electricity supply.

What determines the type of scaffolding used on a job?As you will have read in this chapter, only a carded scaffolder is allowed to erect or alter scaffolding. They will select the scaffolding to be used according to the ground condition at the site, whether or not people will be working on the scaffolding, the types of materials and equipment that will be used on the scaffolding and the height to which access will be needed.

FAQ

On the job: Attending to fascia boardsPete has been asked by a client to take a look at all the fascia boards onatwo-storeybuilding.Dependingontheconditionofthefasciaboards,theywill need either repairing or replacing. The job will probably take Pete between two and six hours, depending on what he has to do.

WhattypesofscaffoldingdoyouthinkmightbesuitableforPete’sjob?Canyou think of anything Pete will have to consider while he prepares for and carriesoutthistask?Thinkaboutthingslikeegressandexitpoints,whetheror not the area is closed off to the public and how long Pete will be working at height etc.

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1. Name four different methods of gaining height while working.

2. Whatmustbedonebeforeanyworkatheightiscarriedout?

3. Whatareyourthreehealthandsafetydutieswhenworkingatheight?

4. As a rule, what is the maximum time you should work from a ladder or stepladder?

5. Howshouldawoodenstepladderbecheckedbeforeuse?

6. When storing a wooden pole ladder, why does it need to be evenly supportedalongitslength?

7. Explain the 1:4 (or 75°) ratio rule which should be observed when erecting a ladder.

8. Whenshouldatrestleplatformbeused?

9. Whattwotypesofboardcanbeusedasaplatformwithatrestleframe?

10. Whyshouldyouonlyuseaspeciallydesignedhop-up?

11. Therearetwotypesoftubularscaffolding–whataretheyandhowdotheydiffer?

12. Whataretheeightquestionsyoushouldaskyourselfbeforeusingscaffolding?

13. Inordertoincreasetheheightofatowerscaffold,whatelsehastobeincreasedandbyhowmuch?

14. Howhighshouldscaffoldguardrailsbe?

15. Whatistheonlywayyoushouldaccessscaffolding?

16. Whencansafetynettingbeused?

17. Howdoesanairbagsafetysystemwork?

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